<!doctype html>
<html>
<head>
  <meta charset="utf-8">
  <!-- 该模板由编程导航整理，部分素材可能源于网上，侵删，作者微信 code_nav，公众号『 编程导航 』 -->
  <title>编程导航 - 冲田总司樱花飘落</title>
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  <meta name="keywords" content="编程,程序员,导航,资源,主页,编程导航" />
</head>
<style>
  body {
    padding: 0;
    margin: 0;
    overflow: hidden;

    background-image: url(O.jpg);
    background-position: center center;
    background-repeat: no-repeat;
    background-size: cover;
  }

  canvas {
    padding: 0;
    margin: 0;
    opacity: 0.3;
  }

  div.btnbg {
    position: fixed;
    left: 0;
    top: 0;
  }
</style>
<body>
<canvas id="sakura"></canvas>
<div class="btnbg">
</div>

<!-- sakura shader -->
<script id="sakura_point_vsh" type="x-shader/x_vertex">
uniform mat4 uProjection;
uniform mat4 uModelview;
uniform vec3 uResolution;
uniform vec3 uOffset;
uniform vec3 uDOF;  //x:focus distance, y:focus radius, z:max radius
uniform vec3 uFade; //x:start distance, y:half distance, z:near fade start

attribute vec3 aPosition;
attribute vec3 aEuler;
attribute vec2 aMisc; //x:size, y:fade

varying vec3 pposition;
varying float psize;
varying float palpha;
varying float pdist;

//varying mat3 rotMat;
varying vec3 normX;
varying vec3 normY;
varying vec3 normZ;
varying vec3 normal;

varying float diffuse;
varying float specular;
varying float rstop;
varying float distancefade;

void main(void) {
    // Projection is based on vertical angle
    vec4 pos = uModelview * vec4(aPosition + uOffset, 1.0);
    gl_Position = uProjection * pos;
    gl_PointSize = aMisc.x * uProjection[1][1] / -pos.z * uResolution.y * 0.5;

    pposition = pos.xyz;
    psize = aMisc.x;
    pdist = length(pos.xyz);
    palpha = smoothstep(0.0, 1.0, (pdist - 0.1) / uFade.z);

    vec3 elrsn = sin(aEuler);
    vec3 elrcs = cos(aEuler);
    mat3 rotx = mat3(
        1.0, 0.0, 0.0,
        0.0, elrcs.x, elrsn.x,
        0.0, -elrsn.x, elrcs.x
    );
    mat3 roty = mat3(
        elrcs.y, 0.0, -elrsn.y,
        0.0, 1.0, 0.0,
        elrsn.y, 0.0, elrcs.y
    );
    mat3 rotz = mat3(
        elrcs.z, elrsn.z, 0.0,
        -elrsn.z, elrcs.z, 0.0,
        0.0, 0.0, 1.0
    );
    mat3 rotmat = rotx * roty * rotz;
    normal = rotmat[2];

    mat3 trrotm = mat3(
        rotmat[0][0], rotmat[1][0], rotmat[2][0],
        rotmat[0][1], rotmat[1][1], rotmat[2][1],
        rotmat[0][2], rotmat[1][2], rotmat[2][2]
    );
    normX = trrotm[0];
    normY = trrotm[1];
    normZ = trrotm[2];

    const vec3 lit = vec3(0.6917144638660746, 0.6917144638660746, -0.20751433915982237);

    float tmpdfs = dot(lit, normal);
    if(tmpdfs < 0.0) {
        normal = -normal;
        tmpdfs = dot(lit, normal);
    }
    diffuse = 0.4 + tmpdfs;

    vec3 eyev = normalize(-pos.xyz);
    if(dot(eyev, normal) > 0.0) {
        vec3 hv = normalize(eyev + lit);
        specular = pow(max(dot(hv, normal), 0.0), 20.0);
    }
    else {
        specular = 0.0;
    }

    rstop = clamp((abs(pdist - uDOF.x) - uDOF.y) / uDOF.z, 0.0, 1.0);
    rstop = pow(rstop, 0.5);
    //-0.69315 = ln(0.5)
    distancefade = min(1.0, exp((uFade.x - pdist) * 0.69315 / uFade.y));
}

</script>
<script id="sakura_point_fsh" type="x-shader/x_fragment">
#ifdef GL_ES
//precision mediump float;
precision highp float;
#endif

uniform vec3 uDOF;  //x:focus distance, y:focus radius, z:max radius
uniform vec3 uFade; //x:start distance, y:half distance, z:near fade start

const vec3 fadeCol = vec3(0.08, 0.03, 0.06);

varying vec3 pposition;
varying float psize;
varying float palpha;
varying float pdist;

//varying mat3 rotMat;
varying vec3 normX;
varying vec3 normY;
varying vec3 normZ;
varying vec3 normal;

varying float diffuse;
varying float specular;
varying float rstop;
varying float distancefade;

float ellipse(vec2 p, vec2 o, vec2 r) {
    vec2 lp = (p - o) / r;
    return length(lp) - 1.0;
}

void main(void) {
    vec3 p = vec3(gl_PointCoord - vec2(0.5, 0.5), 0.0) * 2.0;
    vec3 d = vec3(0.0, 0.0, -1.0);
    float nd = normZ.z; //dot(-normZ, d);
    if(abs(nd) < 0.0001) discard;

    float np = dot(normZ, p);
    vec3 tp = p + d * np / nd;
    vec2 coord = vec2(dot(normX, tp), dot(normY, tp));

    //angle = 15 degree
    const float flwrsn = 0.258819045102521;
    const float flwrcs = 0.965925826289068;
    mat2 flwrm = mat2(flwrcs, -flwrsn, flwrsn, flwrcs);
    vec2 flwrp = vec2(abs(coord.x), coord.y) * flwrm;

    float r;
    if(flwrp.x < 0.0) {
        r = ellipse(flwrp, vec2(0.065, 0.024) * 0.5, vec2(0.36, 0.96) * 0.5);
    }
    else {
        r = ellipse(flwrp, vec2(0.065, 0.024) * 0.5, vec2(0.58, 0.96) * 0.5);
    }

    if(r > rstop) discard;

    vec3 col = mix(vec3(1.0, 0.8, 0.75), vec3(1.0, 0.9, 0.87), r);
    float grady = mix(0.0, 1.0, pow(coord.y * 0.5 + 0.5, 0.35));
    col *= vec3(1.0, grady, grady);
    col *= mix(0.8, 1.0, pow(abs(coord.x), 0.3));
    col = col * diffuse + specular;

    col = mix(fadeCol, col, distancefade);

    float alpha = (rstop > 0.001)? (0.5 - r / (rstop * 2.0)) : 1.0;
    alpha = smoothstep(0.0, 1.0, alpha) * palpha;

    gl_FragColor = vec4(col * 0.5, alpha);
}

</script>
<!-- effects -->
<script id="fx_common_vsh" type="x-shader/x_vertex">
uniform vec3 uResolution;
attribute vec2 aPosition;

varying vec2 texCoord;
varying vec2 screenCoord;

void main(void) {
    gl_Position = vec4(aPosition, 0.0, 1.0);
    texCoord = aPosition.xy * 0.5 + vec2(0.5, 0.5);
    screenCoord = aPosition.xy * vec2(uResolution.z, 1.0);
}

</script>
<script id="bg_fsh" type="x-shader/x_fragment">
#ifdef GL_ES
//precision mediump float;
precision highp float;
#endif

uniform vec2 uTimes;

varying vec2 texCoord;
varying vec2 screenCoord;

void main(void) {
    vec3 col;
    float c;
    vec2 tmpv = texCoord * vec2(3, 0.9) - vec2(0.95, 1);
    c = exp(-pow(length(tmpv) * 1.5, 0.3));
    col = mix(vec3(0, 0, 0), vec3(1,1,1) * 1.5, c);
    gl_FragColor = vec4(col * 0.5, 1.0);

}

</script>
<script id="fx_brightbuf_fsh" type="x-shader/x_fragment">
#ifdef GL_ES
//precision mediump float;
precision highp float;
#endif
uniform sampler2D uSrc;
uniform vec2 uDelta;

varying vec2 texCoord;
varying vec2 screenCoord;

void main(void) {
    vec4 col = texture2D(uSrc, texCoord);
    gl_FragColor = vec4(col.rgb * 2.0 - vec3(0.5), 1.0);
}

</script>
<script id="fx_dirblur_r4_fsh" type="x-shader/x_fragment">
#ifdef GL_ES
//precision mediump float;
precision highp float;
#endif
uniform sampler2D uSrc;
uniform vec2 uDelta;
uniform vec4 uBlurDir; //dir(x, y), stride(z, w)

varying vec2 texCoord;
varying vec2 screenCoord;

void main(void) {
    vec4 col = texture2D(uSrc, texCoord);
    col = col + texture2D(uSrc, texCoord + uBlurDir.xy * uDelta);
    col = col + texture2D(uSrc, texCoord - uBlurDir.xy * uDelta);
    col = col + texture2D(uSrc, texCoord + (uBlurDir.xy + uBlurDir.zw) * uDelta);
    col = col + texture2D(uSrc, texCoord - (uBlurDir.xy + uBlurDir.zw) * uDelta);
    gl_FragColor = col / 5.0;
}

</script>
<!-- effect fragment shader template -->
<script id="fx_common_fsh" type="x-shader/x_fragment">
#ifdef GL_ES
//precision mediump float;
precision highp float;
#endif
uniform sampler2D uSrc;
uniform vec2 uDelta;

varying vec2 texCoord;
varying vec2 screenCoord;

void main(void) {
    gl_FragColor = texture2D(uSrc, texCoord);
}

</script>
<!-- post processing -->
<script id="pp_final_vsh" type="x-shader/x_vertex">
uniform vec3 uResolution;
attribute vec2 aPosition;
varying vec2 texCoord;
varying vec2 screenCoord;
void main(void) {
    gl_Position = vec4(aPosition, 0.0, 1.0);
    texCoord = aPosition.xy * 0.5 + vec2(0.5, 0.5);
    screenCoord = aPosition.xy * vec2(uResolution.z, 1.0);
}

</script>
<script id="pp_final_fsh" type="x-shader/x_fragment">
#ifdef GL_ES
//precision mediump float;
precision highp float;
#endif
uniform sampler2D uSrc;
uniform sampler2D uBloom;
uniform vec2 uDelta;
varying vec2 texCoord;
varying vec2 screenCoord;
void main(void) {
    vec4 srccol = texture2D(uSrc, texCoord) * 2.0;
    vec4 bloomcol = texture2D(uBloom, texCoord);
    vec4 col;
    col = srccol + bloomcol * (vec4(1.0) + srccol);
    col *= smoothstep(1.0, 0.0, pow(length((texCoord - vec2(0.5)) * 2.0), 1.2) * 0.5);
    col = pow(col, vec4(0.45454545454545)); //(1.0 / 2.2)

    gl_FragColor = vec4(col.rgb, 1.0);
    gl_FragColor.a = 1.0;
}

</script>
</body>
<script>
  // Utilities
  var Vector3 = {};
  var Matrix44 = {};
  Vector3.create = function (x, y, z) {
    return {'x': x, 'y': y, 'z': z};
  };
  Vector3.dot = function (v0, v1) {
    return v0.x * v1.x + v0.y * v1.y + v0.z * v1.z;
  };
  Vector3.cross = function (v, v0, v1) {
    v.x = v0.y * v1.z - v0.z * v1.y;
    v.y = v0.z * v1.x - v0.x * v1.z;
    v.z = v0.x * v1.y - v0.y * v1.x;
  };
  Vector3.normalize = function (v) {
    var l = v.x * v.x + v.y * v.y + v.z * v.z;
    if (l > 0.00001) {
      l = 1.0 / Math.sqrt(l);
      v.x *= l;
      v.y *= l;
      v.z *= l;
    }
  };
  Vector3.arrayForm = function (v) {
    if (v.array) {
      v.array[0] = v.x;
      v.array[1] = v.y;
      v.array[2] = v.z;
    } else {
      v.array = new Float32Array([v.x, v.y, v.z]);
    }
    return v.array;
  };
  Matrix44.createIdentity = function () {
    return new Float32Array([1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0]);
  };
  Matrix44.loadProjection = function (m, aspect, vdeg, near, far) {
    var h = near * Math.tan(vdeg * Math.PI / 180.0 * 0.5) * 2.0;
    var w = h * aspect;

    m[0] = 2.0 * near / w;
    m[1] = 0.0;
    m[2] = 0.0;
    m[3] = 0.0;

    m[4] = 0.0;
    m[5] = 2.0 * near / h;
    m[6] = 0.0;
    m[7] = 0.0;

    m[8] = 0.0;
    m[9] = 0.0;
    m[10] = -(far + near) / (far - near);
    m[11] = -1.0;

    m[12] = 0.0;
    m[13] = 0.0;
    m[14] = -2.0 * far * near / (far - near);
    m[15] = 0.0;
  };
  Matrix44.loadLookAt = function (m, vpos, vlook, vup) {
    var frontv = Vector3.create(vpos.x - vlook.x, vpos.y - vlook.y, vpos.z - vlook.z);
    Vector3.normalize(frontv);
    var sidev = Vector3.create(1.0, 0.0, 0.0);
    Vector3.cross(sidev, vup, frontv);
    Vector3.normalize(sidev);
    var topv = Vector3.create(1.0, 0.0, 0.0);
    Vector3.cross(topv, frontv, sidev);
    Vector3.normalize(topv);

    m[0] = sidev.x;
    m[1] = topv.x;
    m[2] = frontv.x;
    m[3] = 0.0;

    m[4] = sidev.y;
    m[5] = topv.y;
    m[6] = frontv.y;
    m[7] = 0.0;

    m[8] = sidev.z;
    m[9] = topv.z;
    m[10] = frontv.z;
    m[11] = 0.0;

    m[12] = -(vpos.x * m[0] + vpos.y * m[4] + vpos.z * m[8]);
    m[13] = -(vpos.x * m[1] + vpos.y * m[5] + vpos.z * m[9]);
    m[14] = -(vpos.x * m[2] + vpos.y * m[6] + vpos.z * m[10]);
    m[15] = 1.0;
  };

  //
  var timeInfo = {
    'start': 0, 'prev': 0, // Date
    'delta': 0, 'elapsed': 0 // Number(sec)
  };

  //
  var gl;
  var renderSpec = {
    'width': 0,
    'height': 0,
    'aspect': 1,
    'array': new Float32Array(3),
    'halfWidth': 0,
    'halfHeight': 0,
    'halfArray': new Float32Array(3)
    // and some render targets. see setViewport()
  };
  renderSpec.setSize = function (w, h) {
    renderSpec.width = w;
    renderSpec.height = h;
    renderSpec.aspect = renderSpec.width / renderSpec.height;
    renderSpec.array[0] = renderSpec.width;
    renderSpec.array[1] = renderSpec.height;
    renderSpec.array[2] = renderSpec.aspect;

    renderSpec.halfWidth = Math.floor(w / 2);
    renderSpec.halfHeight = Math.floor(h / 2);
    renderSpec.halfArray[0] = renderSpec.halfWidth;
    renderSpec.halfArray[1] = renderSpec.halfHeight;
    renderSpec.halfArray[2] = renderSpec.halfWidth / renderSpec.halfHeight;
  };

  function deleteRenderTarget(rt) {
    gl.deleteFramebuffer(rt.frameBuffer);
    gl.deleteRenderbuffer(rt.renderBuffer);
    gl.deleteTexture(rt.texture);
  }

  function createRenderTarget(w, h) {
    var ret = {
      'width': w,
      'height': h,
      'sizeArray': new Float32Array([w, h, w / h]),
      'dtxArray': new Float32Array([1.0 / w, 1.0 / h])
    };
    ret.frameBuffer = gl.createFramebuffer();
    ret.renderBuffer = gl.createRenderbuffer();
    ret.texture = gl.createTexture();

    gl.bindTexture(gl.TEXTURE_2D, ret.texture);
    gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, w, h, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);

    gl.bindFramebuffer(gl.FRAMEBUFFER, ret.frameBuffer);
    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, ret.texture, 0);

    gl.bindRenderbuffer(gl.RENDERBUFFER, ret.renderBuffer);
    gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, w, h);
    gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, ret.renderBuffer);

    gl.bindTexture(gl.TEXTURE_2D, null);
    gl.bindRenderbuffer(gl.RENDERBUFFER, null);
    gl.bindFramebuffer(gl.FRAMEBUFFER, null);

    return ret;
  }

  function compileShader(shtype, shsrc) {
    var retsh = gl.createShader(shtype);

    gl.shaderSource(retsh, shsrc);
    gl.compileShader(retsh);

    if (!gl.getShaderParameter(retsh, gl.COMPILE_STATUS)) {
      var errlog = gl.getShaderInfoLog(retsh);
      gl.deleteShader(retsh);
      console.error(errlog);
      return null;
    }
    return retsh;
  }

  function createShader(vtxsrc, frgsrc, uniformlist, attrlist) {
    var vsh = compileShader(gl.VERTEX_SHADER, vtxsrc);
    var fsh = compileShader(gl.FRAGMENT_SHADER, frgsrc);

    if (vsh == null || fsh == null) {
      return null;
    }

    var prog = gl.createProgram();
    gl.attachShader(prog, vsh);
    gl.attachShader(prog, fsh);

    gl.deleteShader(vsh);
    gl.deleteShader(fsh);

    gl.linkProgram(prog);
    if (!gl.getProgramParameter(prog, gl.LINK_STATUS)) {
      var errlog = gl.getProgramInfoLog(prog);
      console.error(errlog);
      return null;
    }

    if (uniformlist) {
      prog.uniforms = {};
      for (var i = 0; i < uniformlist.length; i++) {
        prog.uniforms[uniformlist[i]] = gl.getUniformLocation(prog, uniformlist[i]);
      }
    }

    if (attrlist) {
      prog.attributes = {};
      for (var i = 0; i < attrlist.length; i++) {
        var attr = attrlist[i];
        prog.attributes[attr] = gl.getAttribLocation(prog, attr);
      }
    }

    return prog;
  }

  function useShader(prog) {
    gl.useProgram(prog);
    for (var attr in prog.attributes) {
      gl.enableVertexAttribArray(prog.attributes[attr]);
      ;
    }
  }

  function unuseShader(prog) {
    for (var attr in prog.attributes) {
      gl.disableVertexAttribArray(prog.attributes[attr]);
      ;
    }
    gl.useProgram(null);
  }

  /////
  var projection = {
    'angle': 60,
    'nearfar': new Float32Array([0.1, 100.0]),
    'matrix': Matrix44.createIdentity()
  };
  var camera = {
    'position': Vector3.create(0, 0, 100),
    'lookat': Vector3.create(0, 0, 0),
    'up': Vector3.create(0, 1, 0),
    'dof': Vector3.create(10.0, 4.0, 8.0),
    'matrix': Matrix44.createIdentity()
  };

  var pointFlower = {};
  var meshFlower = {};
  var sceneStandBy = false;

  var BlossomParticle = function () {
    this.velocity = new Array(3);
    this.rotation = new Array(3);
    this.position = new Array(3);
    this.euler = new Array(3);
    this.size = 1.0;
    this.alpha = 1.0;
    this.zkey = 0.0;
  };

  BlossomParticle.prototype.setVelocity = function (vx, vy, vz) {
    this.velocity[0] = vx;
    this.velocity[1] = vy;
    this.velocity[2] = vz;
  };

  BlossomParticle.prototype.setRotation = function (rx, ry, rz) {
    this.rotation[0] = rx;
    this.rotation[1] = ry;
    this.rotation[2] = rz;
  };

  BlossomParticle.prototype.setPosition = function (nx, ny, nz) {
    this.position[0] = nx;
    this.position[1] = ny;
    this.position[2] = nz;
  };

  BlossomParticle.prototype.setEulerAngles = function (rx, ry, rz) {
    this.euler[0] = rx;
    this.euler[1] = ry;
    this.euler[2] = rz;
  };

  BlossomParticle.prototype.setSize = function (s) {
    this.size = s;
  };

  BlossomParticle.prototype.update = function (dt, et) {
    this.position[0] += this.velocity[0] * dt;
    this.position[1] += this.velocity[1] * dt;
    this.position[2] += this.velocity[2] * dt;

    this.euler[0] += this.rotation[0] * dt;
    this.euler[1] += this.rotation[1] * dt;
    this.euler[2] += this.rotation[2] * dt;
  };

  function createPointFlowers() {
    // get point sizes
    var prm = gl.getParameter(gl.ALIASED_POINT_SIZE_RANGE);
    renderSpec.pointSize = {'min': prm[0], 'max': prm[1]};

    var vtxsrc = document.getElementById("sakura_point_vsh").textContent;
    var frgsrc = document.getElementById("sakura_point_fsh").textContent;

    pointFlower.program = createShader(
      vtxsrc, frgsrc,
      ['uProjection', 'uModelview', 'uResolution', 'uOffset', 'uDOF', 'uFade'],
      ['aPosition', 'aEuler', 'aMisc']
    );

    useShader(pointFlower.program);
    pointFlower.offset = new Float32Array([0.0, 0.0, 0.0]);
    pointFlower.fader = Vector3.create(0.0, 10.0, 0.0);

    // paramerters: velocity[3], rotate[3]
    pointFlower.numFlowers = 100;
    pointFlower.particles = new Array(pointFlower.numFlowers);
    // vertex attributes {position[3], euler_xyz[3], size[1]}
    pointFlower.dataArray = new Float32Array(pointFlower.numFlowers * (3 + 3 + 2));
    pointFlower.positionArrayOffset = 0;
    pointFlower.eulerArrayOffset = pointFlower.numFlowers * 3;
    pointFlower.miscArrayOffset = pointFlower.numFlowers * 6;

    pointFlower.buffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, pointFlower.buffer);
    gl.bufferData(gl.ARRAY_BUFFER, pointFlower.dataArray, gl.DYNAMIC_DRAW);
    gl.bindBuffer(gl.ARRAY_BUFFER, null);

    unuseShader(pointFlower.program);

    for (var i = 0; i < pointFlower.numFlowers; i++) {
      pointFlower.particles[i] = new BlossomParticle();
    }
  }

  function initPointFlowers() {
    //area
    pointFlower.area = Vector3.create(20.0, 20.0, 20.0);
    pointFlower.area.x = pointFlower.area.y * renderSpec.aspect;

    pointFlower.fader.x = 10.0; //env fade start
    pointFlower.fader.y = pointFlower.area.z; //env fade half
    pointFlower.fader.z = 0.1;  //near fade start

    //particles
    var PI2 = Math.PI * 2.0;
    var tmpv3 = Vector3.create(0, 0, 0);
    var tmpv = 0;
    var symmetryrand = function () {
      return (Math.random() * 2.0 - 1.0);
    };
    for (var i = 0; i < pointFlower.numFlowers; i++) {
      var tmpprtcl = pointFlower.particles[i];

      //velocity
      tmpv3.x = symmetryrand() * 0.3 + 0.8;
      tmpv3.y = symmetryrand() * 0.2 - 1.0;
      tmpv3.z = symmetryrand() * 0.3 + 0.5;
      Vector3.normalize(tmpv3);
      tmpv = 2.0 + Math.random() * 1.0;
      tmpprtcl.setVelocity(tmpv3.x * tmpv, tmpv3.y * tmpv, tmpv3.z * tmpv);

      //rotation
      tmpprtcl.setRotation(
        symmetryrand() * PI2 * 0.5,
        symmetryrand() * PI2 * 0.5,
        symmetryrand() * PI2 * 0.5
      );

      //position
      tmpprtcl.setPosition(
        symmetryrand() * pointFlower.area.x,
        symmetryrand() * pointFlower.area.y,
        symmetryrand() * pointFlower.area.z
      );

      //euler
      tmpprtcl.setEulerAngles(
        Math.random() * Math.PI * 2.0,
        Math.random() * Math.PI * 2.0,
        Math.random() * Math.PI * 2.0
      );

      //size
      tmpprtcl.setSize(0.9 + Math.random() * 0.1);
    }
  }

  function renderPointFlowers() {
    //update
    var PI2 = Math.PI * 2.0;
    var limit = [pointFlower.area.x, pointFlower.area.y, pointFlower.area.z];
    var repeatPos = function (prt, cmp, limit) {
      if (Math.abs(prt.position[cmp]) - prt.size * 0.5 > limit) {
        //out of area
        if (prt.position[cmp] > 0) {
          prt.position[cmp] -= limit * 2.0;
        } else {
          prt.position[cmp] += limit * 2.0;
        }
      }
    };
    var repeatEuler = function (prt, cmp) {
      prt.euler[cmp] = prt.euler[cmp] % PI2;
      if (prt.euler[cmp] < 0.0) {
        prt.euler[cmp] += PI2;
      }
    };

    for (var i = 0; i < pointFlower.numFlowers; i++) {
      var prtcl = pointFlower.particles[i];
      prtcl.update(timeInfo.delta, timeInfo.elapsed);
      repeatPos(prtcl, 0, pointFlower.area.x);
      repeatPos(prtcl, 1, pointFlower.area.y);
      repeatPos(prtcl, 2, pointFlower.area.z);
      repeatEuler(prtcl, 0);
      repeatEuler(prtcl, 1);
      repeatEuler(prtcl, 2);

      prtcl.alpha = 1.0;//(pointFlower.area.z - prtcl.position[2]) * 0.5;

      prtcl.zkey = (camera.matrix[2] * prtcl.position[0]
        + camera.matrix[6] * prtcl.position[1]
        + camera.matrix[10] * prtcl.position[2]
        + camera.matrix[14]);
    }

    // sort
    pointFlower.particles.sort(function (p0, p1) {
      return p0.zkey - p1.zkey;
    });

    // update data
    var ipos = pointFlower.positionArrayOffset;
    var ieuler = pointFlower.eulerArrayOffset;
    var imisc = pointFlower.miscArrayOffset;
    for (var i = 0; i < pointFlower.numFlowers; i++) {
      var prtcl = pointFlower.particles[i];
      pointFlower.dataArray[ipos] = prtcl.position[0];
      pointFlower.dataArray[ipos + 1] = prtcl.position[1];
      pointFlower.dataArray[ipos + 2] = prtcl.position[2];
      ipos += 3;
      pointFlower.dataArray[ieuler] = prtcl.euler[0];
      pointFlower.dataArray[ieuler + 1] = prtcl.euler[1];
      pointFlower.dataArray[ieuler + 2] = prtcl.euler[2];
      ieuler += 3;
      pointFlower.dataArray[imisc] = prtcl.size;
      pointFlower.dataArray[imisc + 1] = prtcl.alpha;
      imisc += 2;
    }

    //draw
    gl.enable(gl.BLEND);
    //gl.disable(gl.DEPTH_TEST);
    gl.blendFunc(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA);

    var prog = pointFlower.program;
    useShader(prog);

    gl.uniformMatrix4fv(prog.uniforms.uProjection, false, projection.matrix);
    gl.uniformMatrix4fv(prog.uniforms.uModelview, false, camera.matrix);
    gl.uniform3fv(prog.uniforms.uResolution, renderSpec.array);
    gl.uniform3fv(prog.uniforms.uDOF, Vector3.arrayForm(camera.dof));
    gl.uniform3fv(prog.uniforms.uFade, Vector3.arrayForm(pointFlower.fader));

    gl.bindBuffer(gl.ARRAY_BUFFER, pointFlower.buffer);
    gl.bufferData(gl.ARRAY_BUFFER, pointFlower.dataArray, gl.DYNAMIC_DRAW);

    gl.vertexAttribPointer(prog.attributes.aPosition, 3, gl.FLOAT, false, 0, pointFlower.positionArrayOffset * Float32Array.BYTES_PER_ELEMENT);
    gl.vertexAttribPointer(prog.attributes.aEuler, 3, gl.FLOAT, false, 0, pointFlower.eulerArrayOffset * Float32Array.BYTES_PER_ELEMENT);
    gl.vertexAttribPointer(prog.attributes.aMisc, 2, gl.FLOAT, false, 0, pointFlower.miscArrayOffset * Float32Array.BYTES_PER_ELEMENT);

    // doubler
    for (var i = 1; i < 2; i++) {
      var zpos = i * -2.0;
      pointFlower.offset[0] = pointFlower.area.x * -1.0;
      pointFlower.offset[1] = pointFlower.area.y * -1.0;
      pointFlower.offset[2] = pointFlower.area.z * zpos;
      gl.uniform3fv(prog.uniforms.uOffset, pointFlower.offset);
      gl.drawArrays(gl.POINT, 0, pointFlower.numFlowers);

      pointFlower.offset[0] = pointFlower.area.x * -1.0;
      pointFlower.offset[1] = pointFlower.area.y * 1.0;
      pointFlower.offset[2] = pointFlower.area.z * zpos;
      gl.uniform3fv(prog.uniforms.uOffset, pointFlower.offset);
      gl.drawArrays(gl.POINT, 0, pointFlower.numFlowers);

      pointFlower.offset[0] = pointFlower.area.x * 1.0;
      pointFlower.offset[1] = pointFlower.area.y * -1.0;
      pointFlower.offset[2] = pointFlower.area.z * zpos;
      gl.uniform3fv(prog.uniforms.uOffset, pointFlower.offset);
      gl.drawArrays(gl.POINT, 0, pointFlower.numFlowers);

      pointFlower.offset[0] = pointFlower.area.x * 1.0;
      pointFlower.offset[1] = pointFlower.area.y * 1.0;
      pointFlower.offset[2] = pointFlower.area.z * zpos;
      gl.uniform3fv(prog.uniforms.uOffset, pointFlower.offset);
      gl.drawArrays(gl.POINT, 0, pointFlower.numFlowers);
    }

    //main
    pointFlower.offset[0] = 0.0;
    pointFlower.offset[1] = 0.0;
    pointFlower.offset[2] = 0.0;
    gl.uniform3fv(prog.uniforms.uOffset, pointFlower.offset);
    gl.drawArrays(gl.POINT, 0, pointFlower.numFlowers);

    gl.bindBuffer(gl.ARRAY_BUFFER, null);
    unuseShader(prog);

    gl.enable(gl.DEPTH_TEST);
    gl.disable(gl.BLEND);
  }

  // effects
  //common util
  function createEffectProgram(vtxsrc, frgsrc, exunifs, exattrs) {
    var ret = {};
    var unifs = ['uResolution', 'uSrc', 'uDelta'];
    if (exunifs) {
      unifs = unifs.concat(exunifs);
    }
    var attrs = ['aPosition'];
    if (exattrs) {
      attrs = attrs.concat(exattrs);
    }

    ret.program = createShader(vtxsrc, frgsrc, unifs, attrs);
    useShader(ret.program);

    ret.dataArray = new Float32Array([
      -1.0, -1.0,
      1.0, -1.0,
      -1.0, 1.0,
      1.0, 1.0
    ]);
    ret.buffer = gl.createBuffer();
    gl.bindBuffer(gl.ARRAY_BUFFER, ret.buffer);
    gl.bufferData(gl.ARRAY_BUFFER, ret.dataArray, gl.STATIC_DRAW);

    gl.bindBuffer(gl.ARRAY_BUFFER, null);
    unuseShader(ret.program);

    return ret;
  }

  // basic usage
  // useEffect(prog, srctex({'texture':texid, 'dtxArray':(f32)[dtx, dty]})); //basic initialize
  // gl.uniform**(...); //additional uniforms
  // drawEffect()
  // unuseEffect(prog)
  // TEXTURE0 makes src
  function useEffect(fxobj, srctex) {
    var prog = fxobj.program;
    useShader(prog);
    gl.uniform3fv(prog.uniforms.uResolution, renderSpec.array);

    if (srctex != null) {
      gl.uniform2fv(prog.uniforms.uDelta, srctex.dtxArray);
      gl.uniform1i(prog.uniforms.uSrc, 0);

      gl.activeTexture(gl.TEXTURE0);
      gl.bindTexture(gl.TEXTURE_2D, srctex.texture);
    }
  }

  function drawEffect(fxobj) {
    gl.bindBuffer(gl.ARRAY_BUFFER, fxobj.buffer);
    gl.vertexAttribPointer(fxobj.program.attributes.aPosition, 2, gl.FLOAT, false, 0, 0);
    gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
  }

  function unuseEffect(fxobj) {
    unuseShader(fxobj.program);
  }

  var effectLib = {};

  function createEffectLib() {

    var vtxsrc, frgsrc;
    //common
    var cmnvtxsrc = document.getElementById("fx_common_vsh").textContent;

    //background
    frgsrc = document.getElementById("bg_fsh").textContent;
    effectLib.sceneBg = createEffectProgram(cmnvtxsrc, frgsrc, ['uTimes'], null);


    // make brightpixels buffer
    frgsrc = document.getElementById("fx_brightbuf_fsh").textContent;
    effectLib.mkBrightBuf = createEffectProgram(cmnvtxsrc, frgsrc, null, null);

    // direction blur
    frgsrc = document.getElementById("fx_dirblur_r4_fsh").textContent;
    effectLib.dirBlur = createEffectProgram(cmnvtxsrc, frgsrc, ['uBlurDir'], null);

    //final composite
    vtxsrc = document.getElementById("pp_final_vsh").textContent;
    frgsrc = document.getElementById("pp_final_fsh").textContent;
    effectLib.finalComp = createEffectProgram(vtxsrc, frgsrc, ['uBloom'], null);
  }

  // background
  function createBackground() {
    function initTexture(gl, shaderProgram, n) {
      //创建纹理对象
      var texture = gl.createTexture();
      //获取u_Sampler的存储位置
      var u_Sampler = gl.getUniformLocation(shaderProgram, 'u_Sampler');

      //创建image对象
      var image = new Image();

      //加载纹理
      image.onload = function () {
        loadTexture(gl, n, texture, u_Sampler, image);
      };
      // 浏览器开始加载图片 注意：一定是2^mx2^n尺寸的图片
      image.src = "1.jpg";
      return true;

    }
  }

  function initBackground() {
    //console.log("init background");
  }

  function renderBackground() {
    gl.disable(gl.DEPTH_TEST);

    useEffect(effectLib.sceneBg, null);
    gl.uniform2f(effectLib.sceneBg.program.uniforms.uTimes, timeInfo.elapsed, timeInfo.delta);
    drawEffect(effectLib.sceneBg);
    unuseEffect(effectLib.sceneBg);

    gl.enable(gl.DEPTH_TEST);
  }

  // post process
  var postProcess = {};

  function createPostProcess() {
    //console.log("create post process");
  }

  function initPostProcess() {
    //console.log("init post process");
  }

  function renderPostProcess() {
    gl.enable(gl.TEXTURE_2D);
    gl.disable(gl.DEPTH_TEST);
    var bindRT = function (rt, isclear) {
      gl.bindFramebuffer(gl.FRAMEBUFFER, rt.frameBuffer);
      gl.viewport(0, 0, rt.width, rt.height);
      if (isclear) {
        gl.clearColor(0, 0, 0, 0);
        gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

      }
    };

    //make bright buff
    bindRT(renderSpec.wHalfRT0, true);
    useEffect(effectLib.mkBrightBuf, renderSpec.mainRT);
    drawEffect(effectLib.mkBrightBuf);
    unuseEffect(effectLib.mkBrightBuf);

    // make bloom
    for (var i = 0; i < 2; i++) {
      var p = 1.5 + 1 * i;
      var s = 2.0 + 1 * i;
      bindRT(renderSpec.wHalfRT1, true);
      useEffect(effectLib.dirBlur, renderSpec.wHalfRT0);
      gl.uniform4f(effectLib.dirBlur.program.uniforms.uBlurDir, p, 0.0, s, 0.0);
      drawEffect(effectLib.dirBlur);
      unuseEffect(effectLib.dirBlur);

      bindRT(renderSpec.wHalfRT0, true);
      useEffect(effectLib.dirBlur, renderSpec.wHalfRT1);
      gl.uniform4f(effectLib.dirBlur.program.uniforms.uBlurDir, 0.0, p, 0.0, s);
      drawEffect(effectLib.dirBlur);
      unuseEffect(effectLib.dirBlur);
    }

    //display
    gl.bindFramebuffer(gl.FRAMEBUFFER, null);
    gl.viewport(0, 0, renderSpec.width, renderSpec.height);
    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

    useEffect(effectLib.finalComp, renderSpec.mainRT);
    gl.uniform1i(effectLib.finalComp.program.uniforms.uBloom, 1);
    gl.activeTexture(gl.TEXTURE1);
    gl.bindTexture(gl.TEXTURE_2D, renderSpec.wHalfRT0.texture);
    drawEffect(effectLib.finalComp);
    unuseEffect(effectLib.finalComp);

    gl.enable(gl.DEPTH_TEST);
  }

  /////
  var SceneEnv = {};

  function createScene() {
    createEffectLib();
    createBackground();
    createPointFlowers();
    createPostProcess();
    sceneStandBy = true;
  }

  function initScene() {
    initBackground();
    initPointFlowers();
    initPostProcess();

    //camera.position.z = 17.320508;
    camera.position.z = pointFlower.area.z + projection.nearfar[0];
    projection.angle = Math.atan2(pointFlower.area.y, camera.position.z + pointFlower.area.z) * 180.0 / Math.PI * 2.0;
    Matrix44.loadProjection(projection.matrix, renderSpec.aspect, projection.angle, projection.nearfar[0], projection.nearfar[1]);
  }

  function renderScene() {
    //draw
    Matrix44.loadLookAt(camera.matrix, camera.position, camera.lookat, camera.up);

    gl.enable(gl.DEPTH_TEST);

    //gl.bindFramebuffer(gl.FRAMEBUFFER, null);
    gl.bindFramebuffer(gl.FRAMEBUFFER, renderSpec.mainRT.frameBuffer);
    gl.viewport(0, 0, renderSpec.mainRT.width, renderSpec.mainRT.height);
    gl.clearColor(0, 0, 0, 0);
    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);


    renderPointFlowers();
    renderPostProcess();
  }

  /////
  function onResize(e) {
    makeCanvasFullScreen(document.getElementById("sakura"));
    setViewports();
    if (sceneStandBy) {
      initScene();
    }
  }

  function setViewports() {
    renderSpec.setSize(gl.canvas.width, gl.canvas.height);

    gl.clearColor(0.2, 0.2, 0.5, 1.0);
    gl.viewport(0, 0, renderSpec.width, renderSpec.height);

    var rtfunc = function (rtname, rtw, rth) {
      var rt = renderSpec[rtname];
      if (rt) deleteRenderTarget(rt);
      renderSpec[rtname] = createRenderTarget(rtw, rth);
    };
    rtfunc('mainRT', renderSpec.width, renderSpec.height);
    rtfunc('wFullRT0', renderSpec.width, renderSpec.height);
    rtfunc('wFullRT1', renderSpec.width, renderSpec.height);
    rtfunc('wHalfRT0', renderSpec.halfWidth, renderSpec.halfHeight);
    rtfunc('wHalfRT1', renderSpec.halfWidth, renderSpec.halfHeight);
  }

  function render() {
    renderScene();
  }

  var animating = true;

  function toggleAnimation(elm) {
    animating ^= true;
    if (animating) animate();
    if (elm) {
      elm.innerHTML = animating ? "Stop" : "Start";
    }
  }

  function stepAnimation() {
    if (!animating) animate();
  }

  function animate() {
    var curdate = new Date();
    timeInfo.elapsed = (curdate - timeInfo.start) / 1000.0;
    timeInfo.delta = (curdate - timeInfo.prev) / 1000.0;
    timeInfo.prev = curdate;

    if (animating) requestAnimationFrame(animate);
    render();
  }


  function makeCanvasFullScreen(canvas) {
    var b = document.body;
    var d = document.documentElement;
    fullw = Math.max(b.clientWidth, b.scrollWidth, d.scrollWidth, d.clientWidth);
    fullh = Math.max(b.clientHeight, b.scrollHeight, d.scrollHeight, d.clientHeight);
    canvas.width = fullw;
    canvas.height = fullh;
  }

  window.addEventListener('load', function (e) {
    var canvas = document.getElementById("sakura");
    try {
      makeCanvasFullScreen(canvas);
      gl = canvas.getContext('experimental-webgl');
    } catch (e) {
      alert("WebGL not supported." + e);
      console.error(e);
      return;
    }

    window.addEventListener('resize', onResize);

    setViewports();
    createScene();
    initScene();

    timeInfo.start = new Date();
    timeInfo.prev = timeInfo.start;
    animate();
  });

  //set window.requestAnimationFrame
  (function (w, r) {
    w['r' + r] = w['r' + r] || w['webkitR' + r] || w['mozR' + r] || w['msR' + r] || w['oR' + r] || function (c) {
      w.setTimeout(c, 1000 / 60);
    };
  })(window, 'equestAnimationFrame');
</script>
</html>
